Preheat oven to 400º F/200°C. Line a standard muffin tin with paper liners.
In a bowl, whisk together oil, egg, milk, sugar, and vanilla and set aside.
In a large bowl, mix together flour, salt, baking powder, and cinnamon. Make a well in the center of the dry ingredients and pour in the wet ingredient mixture. Mix together until just combined.
In a small bowl toss the blueberries with flour. This will help prevent them from sinking to the bottom of the muffins during baking. Gently fold the flour-coated blueberries into the batter.
In a bowl, mix together the dry ingredients for the topping. Add the butter/oil and mix with your fingers until you have large crumbs.
Scoop the muffin batter into prepared tins and generously pack the crumb topping on top.
Bake for 15-20 minutes or until a toothpick inserted in the center of a muffin comes out clean.
Meanwhile, prepare the glaze. Combine all ingredients, adding milk until you have a drizzle consistency. Allow the muffins to cool before drizzling them with the glaze.
Recipe by Between Carpools at https://betweencarpools.com/will-eating-muffins-breakfast-tomorrow/